diff --git a/src/main/java/com/canonical/openssl/md/OpenSSLMD.java b/src/main/java/com/canonical/openssl/md/OpenSSLMD.java
index db2dc0b..ac354cc 100644
--- a/src/main/java/com/canonical/openssl/md/OpenSSLMD.java
+++ b/src/main/java/com/canonical/openssl/md/OpenSSLMD.java
@@ -82,7 +82,7 @@ protected int engineDigest(byte[] buf, int offset, int len) throws DigestExcepti
     @Override
     protected void engineReset() {
         nativeHandle = doInit0(mdName);
-        cleanable = cleaner.register(nativeHandle, new MDState(nativeHandle));
+        cleanable = cleaner.register(this, new MDState(nativeHandle));
     }
 
     @Override
@@ -104,7 +104,7 @@ private void engineUpdate(byte[] data) {
         synchronized(this) {
            if (!this.initialized) {
                nativeHandle = doInit0(mdName);
-               cleanable = cleaner.register(nativeHandle, new MDState(nativeHandle));
+               cleanable = cleaner.register(this, new MDState(nativeHandle));
                this.initialized = true;
            }
         }